One very important tool on the standard toolbar is the SOLVE tool on the far right of the toolbar. This is what you press after you have entered the data and you are ready to solve the problem. Alternatively, you may use File, Solve or press the [F9] key. Please note that after pressing the SOLVE tool, this tool will change to an EDIT tool. This is how you go back and forth from entering data to viewing the solution. For two modules, linear programming and transportation, there is one more command that will appear on the standard toolbar. This is the STEP tool (not displayed in the figure), and it enables you to step through the iterations, displaying one iteration at a time.